Abstract
The feasibility of treating tannery wastewater having high organic loads was studied using ceramic membrane based
microfiltration process. The common effluent treatment plant (CETP) of a centralized leather complex was selected for the study
which accommodates about 450 tanneries in the city, processing hides from raw to finished products. Effluent sample was
collected from different locations of the CETP, i.e. untreated composite effluent, effluent from primary clarifier and from
equalisation tank. The effluent had varying chemical oxygen demand (COD) and biochemical oxygen demand (BOD) values of
18,480-1500 mg/L and 5720-880 mg/L, respectively and turbidity of 2480-604 NTU. Prior to microfiltration study composite
effluent was subjected to biological pretreatment using activated sludge collected from the common effluent treatment plant. The
dried biomass was characterized by Fourier transform infrared spectroscopy (FT-IR). Crossflow microfiltration (CMF) study was
conducted using indigenously developed porous ceramic membranes by the Central Glass and Ceramic Research Institute from
cost effective composition of α-alumina and clay. COD and sulphide removal efficiency was observed with time for the direct
microfiltration and microfiltration of pretreated effluent. The combined process was found highly effective for COD and sulphide
removal. Depending on the initial loadings, about 67-92% removal of COD and 98-99% reduction of sulphide was obtained in
the combined process whereas, in the single stage process, the removal was 48-68% and 60-65%, respectively. Membrane
fouling was investigated using the linearized forms of cake formation equations obtained by Wiesener and Aptel.